There used to be a regular (I hesitate to say "parliamentary") service from Stratford via those curves. I don't think that it survived the transfer of services to London Overground.

The Seven Sisters - South Tottenham curve is used for reversing southbound trains terminating at Seven Sisters. Currently this is only during engineering work but there was talk of improving frequencies north of Seven Sisters by terminating additional trains, for which LST does not have capacity, there. I don't know if anything is going to come of that idea/

I can't remember a Southend daytime service in the 60s early 70s that wasn't operated by a pair of different classes. I assume 307 + 308 as it was always one with a flat front and one with a sloped cab window. Again I don't recall single units running.

I'm surprised because I didn't think there were enough of the "sloping front" (ie 305/308) emus to allow that. There were only 133-165 and 501-519, so 52 4-car units, to cover all the main line beyond Shenfield out to Clacton that weren't 309 express units, including all the peak extras, and all the Lea valley to Hertford and Bishops Stortford, especially once the Tottenham Hale line was electrified in the early 1970s without any extra electric stock.

Regarding the chance of two 307s being operated pantograph-to-pantograph, how could they get turned? I can only think of the Colchester triangle, well beyond their orbit, as a place to do this on the electric lines.

In the early days class 307 sets were generally seen coupled to class 308/1 sets. I agree that there weren't enough 308/1s to match the number of 307s but this did seem to be the norm. Furthermore, only the higher numbered 308/1s seemed to be on the Southend/Chelmsford services. I had the impression that the lower numbered sets were on fast services beyond Chelmsford to Colchester and Clacton (based at Clacton?) - but I was very young and may have been wrong. The service pattern (off peak) was three trains an hour stopping at Stratford, Ilford, Romford, then all stations to Southend (2 trains per hour) and Chelmsford (1 train per hour). I think there was another service fast to Shenfield to plug the gap in the Southend service. I think that Class 307s did get turned (but I might have been wrong). Could they have been turned in the maze of tracks around Stratford?

Class 306s worked off peak to Gidea Park and in the peaks to Shenfield (and at night to Southend). They were never turned.

I also think that class 305/2 sets were generally on the services to Hertford East and Bishops Stortford.

Later the Class 305/2 sets seemed to be switched to the Southend services – I think that they were basically swapped with class 308/1, but I may have been wrong. Certainly the Class 308/1s became rare on Southend services.

I very rarely saw class 305/1 sets on anything other than Enfield and Chingford services.

Class 302s seemed to turn up on anything – but again my recollections aren’t that clear.

I don’t recall when peak services to Southend were extended to 12 coaches and how this affected formations and allocations. Was this when the class 312s were introduced? I remember the 2-car class 309 units being extended to 4 cars so that 12 coach fast trains could run to Clacton.

In the early days class 307 sets were generally seen coupled to class 308/1 sets. I agree that there weren't enough 308/1s to match the number of 307s but this did seem to be the norm. Furthermore, only the higher numbered 308/1s seemed to be on the Southend/Chelmsford services. I had the impression that the lower numbered sets were on fast services beyond Chelmsford to Colchester and Clacton (based at Clacton?) - but I was very young and may have been wrong. The service pattern (off peak) was three trains an hour stopping at Stratford, Ilford, Romford, then all stations to Southend (2 trains per hour) and Chelmsford (1 train per hour). I think there was another service fast to Shenfield to plug the gap in the Southend service.

When were these 'early days'? I remember the three Southend trains one every 20 mins. There wasn't a Chelmsford service off-peak, instead there was a single 306 unit that ran from Shenfield calling at Ingatestone to Chelmsford and back every hour. There was the hourly Clacton/Walton each way that did Shenfield - Chelmsford (in under 9 minutes!).

Quote:

Originally Posted by Smod

I don’t recall when peak services to Southend were extended to 12 coaches and how this affected formations and allocations. Was this when the class 312s were introduced? I remember the 2-car class 309 units being extended to 4 cars so that 12 coach fast trains could run to Clacton.

The fast peak Southend services (first stop Billericay) were certainly 12-car from 1971 on, the slows (Stratford, Harold Wood then every stop to southend) were 8-car as Stratford, Harold Wood, Brentwood and Shenfield platforms weren't long enough for 12-cars.
The 312s didn't arrive until the mid-'70s when at first they were deployed on the GEML peak services. Their 90mph top speed improved headways over the 75mph 305/308s.
The first 309 modification was for a buffet car from a Trans Pennine DMU to replace one of the original buffet trailers. This was followed by some of the 319/0s having a pair of MKI TSOs sandwiched between the driving cars. There were at least two 319/0s that werent modified by the mid '70s as the 1F80 17:40 LST-Clacton still ran with 2x309/0 (2 car), 1x309/1 & 1x309/2, an impressive performer with a max power of 4512hp available. At the time the class 86s were the most powerful locos with 3600hp.

Regarding the chance of two 307s being operated pantograph-to-pantograph, how could they get turned? I can only think of the Colchester triangle, well beyond their orbit, as a place to do this on the electric lines.

In theory also at Tilbury Riverside.

I can't remember dates but over the years there was tinkering with the timetable to include a fast (to Shenfield) service on the Southend branch although Stratford-Ilford-Romford-all stations every 20 minutes was the norm for most of the time that I remember between the early 60s and early 80s.

Peak hours used to work on a 10 minute cycle, 1 Southend fast from Billericay, 1 Southend Semi, 1 Stopper from Shenfield, 2 from Gidea Park my earliest memory was 1 fast from Romford and 1 fast from Seven Kings but they fiddled with the stopping patterns of these quite early on, 1 from Ilford I think in alternate cycles.

When were these 'early days'? I remember the three Southend trains one every 20 mins. There wasn't a Chelmsford service off-peak, instead there was a single 306 unit that ran from Shenfield calling at Ingatestone to Chelmsford and back every hour. There was the hourly Clacton/Walton each way that did Shenfield - Chelmsford (in under 9 minutes!).

I have found a timetable from 1959 that shows the pattern I described - two Southend and 1 Chelmsford per hour (stopping at Stratford, Ilford Romford...) and one Southend running fast to Shenfield. I have also found a timetable from 1972 showing 3 Southend trains and the Shenfield to Chelmsford shuttle as described above. My recollection is that the 1959 pattern continued well into the 1960s (I wouldn't remember anything from 1959!).

There was a full article about this in an old Modern Railways magazine, just at the end of their old small format so likely 1964. It describes the detailed operation of this sequence. Notable was how the Ilford/Gidea Park frequency was greater than now, although the biggest decline has to be in the Chingford peak hour service which had two 9-car trains every 10 minutes, one nonstop to St James Street Walthamstow.

The magazine article I seem to recall that some services could be run by either the 306 with sliding doors, or the more modern 305/308 with slam doors, and signalmen had to be cautious with the latter in a signal stop at a platform like Stratford, where if people started opening doors to get in a nonstop which had a momentary red, it could cause great disruption.